Pipe mold and ejector



Aug. 9, 1960 B. F. DAWSON, JR

PIPE MOLD AND EJECTOR Filed Feb. 19, 1959 INVENTOR. BENJAMIN F. DAWSON, JR.

AT TO RNEYS United States Patent PIPE MOLD AND EJECTOR Benjamin 1". Dawson, Jr., 3913 SW. Spring Garden, Porfland, Oreg.

Filed Feb. 19, 1959, Ser. No. 794,296

1 Claim. (Cl. 25-120) The present invention relates to an apparatus for ejecting pipes from molds and particularly to an apparatus for ejecting concrete pipes manufactured by the damp tamped method, or the packer head method.

The primary object of the invention is to provide an apparatus of ejecting concrete pipes from molds incorporating a one piece seamless form that can be removed from the pipe without cracking, distorting or defacing the pipe in the removal operation. In order to carry out this object, the seal between the pipe and the casing is first released or broken by the use of air pressure starting the casing to move upwardly from the pipe. After this movement is started additional apparatus is provided for completely removing the casing from the pipe.

Other objects and advantages will become apparent in the following specification when considered in light of the attached drawings, in which:

Figure 1 is a plan view of the apparatus of the invention;

Figure 2 is a vertical sectional view taken on line 2-2 of Figure 1, looking in the direction of the arrows;

Figure 3 is a horizontal sectional view taken on line 3-3 of Figure 2, looking in the direction of the arrows;

Figure 4 is a plan view of the form after the same has been inverted ready to remove the pipe therefrom;

Figure 5 is a vertical sectional view, taken on line 5--5 of Figure 4, looking in the direction indicated;

Figure 6 is a fragmentary sectional view similar to Figure 5, illustrating the casing partially removed; and

Figure 7 is a fragmentary enlarged sectional view similar to Figure 2 illustrating the relationship between the casing, the turntable and the pallet.

Referring now to the drawings in detail wherein like reference characters indicate like parts throughout the several figures, the reference character M indicates generally a concrete pipe mold and the apparatus for removing the pipe therefrom.

The mold M includes a one piece seamless casing 10 in the form of a generally cylindrical drum. The casing 10 has an enlarged bell end 11 integrally formed thereon shaping a bell on a pipe 12 being molded from concrete. The opposite end of the casing 10 has a radial outwardly extending flange 13 arranged to rest on a revolving table 14 of any conventional design. The flange 13 is held to the table 14 by any suitable type of locking means. Lifting handles 15 are provided for lifting and inverting the casing 10 in the operation of the same invention.

The inner walls of the casing 10 may be parallel to one another, but it has been found that tapering them slightly, as shown in the drawings, has certain advantages in the removing of the casing 10 from the pipe 12. The larger diameter of the inner walls being located adjacent the bell end 11 of the casing 10.

I will now describe how the first operation of forming a pipe is accomplished. Referring particularly to Figures 2 and 7, a pallet 16, having a hole 23 therethrough is placed over a centering pin 17 which forms part of the turntable 14. Next, the flange 13 of the casing 10 2,948,044 Patented Aug. 9, 1960 brought to rest on top of the turntable 14, the pallet 16 centering the casing 10. A core 18 supported by the operating shaft 19, is lowered into the casing 10 with the lower end thereof fitted over the centering pin 17, centering the core 18 within the casing 10.

The pipe forming damp mixed concrete 20 is then tamped into the casing 10 from the supply chute 21, indicated by broken lines by any well known means. After the material 20 has been tamped into the casing 10, the core 18 is withdrawn and the casing 10, including the pipe 12, is inverted to the position shown in Figures 4 and 5.

The next operation is to remove the casing 10 from the pipe 12, and it is done in the following manner. A plug 22 is engaged in the opening 23 of the pallet 16. This provides an air tight seal between the pallet 16 and the plug 22. A hood 24, having a flange 25, is bolted to the flange 13 with a sealing gasket 26 therebetween. High pressure air is applied to the interior 27 within the hood 24 through a supply line 28. This causes a high pressure air thrust against the pallet 16 and the upper end of the pipe 12. Part of this air seeps down between the outer periphery of the pipe 12 and the inner surface of the casing 10, breaking the friction existing between the pipe 12 and the casing 10, allowing the casing 10 to be raised, as indicated in Figure 6. From this point on, any well known means (not shown) such as a mechanical mechanism, can be used to completely remove the casing 10 from the pipe 12.

Referring to Figure 5, lifting bales 29, shown by broken lines, may be attached to the lifting handles 15 and operated by any suitable mechanism not here shown for raising the casing 10 completely up and away from the pipe 12.

The use of a one piece seamless casing in the forming of the pipe 12 tends to prevent any cracks or defacing developing in the pipe 12 at any future date. In order to remove conventional casing from the pipe, the same was split or hinged apart, which caused cracks and otherwise defaced the pipe being formed on the removing of the casing.

In order to use a one piece casing, high pressure air, gas or other type of fluid medium is used for breaking the frictional seal between the formed pipe and the casing so that the casing can be removed from the pipe without injurying the same in any way.

Having thus described the preferred embodiment of the invention, it should be understood that numerous structural modifications and adaptations may be resortedto without departing from the scope of the appended claim.

What is claimed is:

A molding apparatus comprising a one piece tubular external mold having a flange at one end, a pallet provided with a central bore engageable in said one piece mold at one end thereof, a resilient plug detachably engageable in said bore, a flanged air dome, means detachably securing said flanges together to secure air dome to said one piece mold at the end thereof adjacent said pallet, an air conduit means connected to said dome for supplying high pressure to the interior of said dome forcing said pallet through said mold and ejecting a molded pipe therefrom, a turntable detachably secured to said flange for supporting one end of one piece mold, and an upstanding boa integrally formed on said turntable centrally thereof, the bore in said pallet engaging over said boss prior to engagement of said plug.

References Cited in the file of this patent UNITED STATES PATENTS 2,331,000 Shaefer Oct. 5, 1943 2,630,600 Boggs Mar, 10, 1953 2,870,513 Gagne Jan. 27, 1959 

